I see Nigel beating both of these. I think Benn big bombs would land on Trinidad in the first 3 rounds and Felix was always a little vulnerable to big hitters Think Pavlik would be more of a boxing match like Benn vs pipper where Benn would wear him down
Benn would always be a dangerous proposition for anyone rising in weight, which is why I don't like the idea of Trinidad fighting him. Pavlik on the otherhand was durable, a decent boxer and had power of his own. And while I'd still favor Nigel, Kelly would be a tough fight.
He beats both.Trinidad in a short brutal fight with both guys hurt possibly on the floor till benn drops the big one and sparks tito out.Pavlik go's longer and is less exciting but benn stops him late possibly when behind on points.
Although Benn is probably the smart pick against both, the sharp punching Trinidad from the William Joppy fight might surprise Benn and get him out of there. I think at his best, he has a better chance for the upset than the somewhat unreliable Pavlik.
A fight between Nigel and Kelly would look like Kelly/Taylor I, except Nigel stops him. Nigel does a Barkley-Demolition Job on Tito. He's just not physical enough to handle Nigel.